This invention relates to double acting power operated log splitters.
Examples of known single-acting hydraulically powered log splitters are shown in U.S. Pat. Nos. 4,284,113 (Nordlin); 4,275,778 (Kotas); 4,103,724 (Braid); 3,242,955 (Hellstrom); and 3,077,214 (Brukner). The pumps, piston-cylinder assemblies and associated connecting lines and controls required for such splitters are relatively heavy, expensive and prone to leakage of hydraulic fluid.
Examples of known double-acting hydraulically powered log splitters are shown in U.S. Pat. Nos. 3,974,867 (Butas) and 3,319,675 (Bles). These double-acting versions suffer from the same drawbacks as mentioned above in connection with hydraulically powered single-acting splitters. Furthermore, because the piston-cylinder assemblies of double-acting splitters must of necessity be offset laterally from the axes of the logs being split, the resulting torques imposed on the seals and O-rings associated with such piston-cylinder assemblies further aggravate leakage problems. Also, because hydraulic pistons necessarily develop different forces during forward and reverse strokes due to the hydraulic displacement of the piston rods, the hydraulic systems of double-acting splitters must be oversized in order to achieve a stated minimum rating. This further increases the size, weight and cost of such systems.
As shown for example in U.S. Pat. No. 4,141,395 (Artz); 4,121,636 (James); 4,116,251 (Graney); 1,283,195 (Hunter); 1,189,999 (Peter); 111,333 (Ficht); and Swiss Pat. No. 231,752 (Suffert-Burner), it is well known to use mechanical threaded spindle or ratchet drives to power single-acting log splitters. However, such systems have not been employed previously in double-acting splitters, inspite of the advantages to be derived from doing so, as will hereinafter become more apparent.